When trying to optimize (i.e., minimize) energy consumption in a computer system, various approaches may be used. Some such approaches consider the higher CPU energy consumption resulting from a faster clock frequency vs. the lower platform energy consumption resulting from finishing the task in less time with that faster clock frequency (“Race to Halt”). A particular algorithm involving this approach, called EARtH, was described by Rotem Efraim et al. in a paper titled “Energy Aware Race to Halt: A Down to Earth Approach for Platform Energy Management” (IEEE & CSDL, Oct. 5, 2012, DOI 10.1109/L-CA.2012.32). However, the EARtH algorithm doesn't account for the power efficiency of the voltage regulator, which may vary with factors such as load conditions, operating voltage etc. Hence, the power-optimized frequency determined by the EARtH algorithm may not produce the actual power-optimized frequency because the EARtH algorithm ignores the interactive effects of the voltage regulator.